Basic science, clinical observation, and epidemiologic studies have all contributed to an emerging body of evidence on the potential role of flavonoids, a group of polyphenolic compounds with antioxidant properties, in the prevention of CVD. However, the few existing studies on flavonoids or its food sources have provided inconsistent results, usually focusing on the primary prevention of coronary heart disease mortality. Therefore, the investigators propose to examine whether flavonoid intake is associated with the risk of incident CVD, and whether specific food sources of flavonoids--including tea, onions, apples, red wine, and other foods--are associated with the risk of incident CVD. The investigators will process and analyze previously collected data of 39,876 middle-aged and older women free of CVD; the Women's Antioxidant Cardiovascular Study (WACS), a prospective study of 8,171 middle-aged and older women with pre-existing CVD or >3 coronary risk factors; the Normative Aging Study (NAS), a prospective study of 2,280 middle-aged and older men; and the Boston Area Health Study (BAHS), a case-control study of first nonfatal Ml in men and women aged <76 years. Using data from semiquantitative food frequency questionnaires administered in each study, the investigators will determine individual intake of flavonoids and its food sources. Unlike previous studies, they will examine flavonoids in relation to both the primary and secondary prevention of incident CVD, consisting of confirmed cases of nonfatal Ml, nonfatal stroke, revascularization procedures, and CVD death. They will have 80% power to detect a significant trend across quartiles with a 32% reduction in CVD risk in the highest quartile for WHS, 31% reduction for WACS, 41% reduction for NAS, and 35% reduction for BAHS. In light of increasing media attention and public awareness on the promise of flavonoids in CVD prevention, this proposal to analyze these four existing databases will provide important new data on flavonoids and its food sources in both the primary and secondary prevention of incident CVD.